Gas turbine plants frequently have multiple burner stages, wherein each burner stage can be supplied individually with fuel. In that context, different burner stages can be realized by different fuel nozzles in one burner, or by each burner stage being assigned at least one burner of its own. Different burner stages will be in operation depending on the load on the turbine plant. For example, at part load or during startup or shutdown of a gas turbine plant, typically not all of the burner stages are in operation. Burner stages which are not in operation are generally sealed in order to prevent ingress of hot combustion gases from the combustion chamber into the burner stage. If the burner stages were previously in operation, they are additionally purged in order to remove, from the fuel supply system and the burners, fuel residue remaining from the previous operation.